HTML output directory sites/simpletest/browser_output is not a writable directory.

PHPUnit 11.5.56 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.3.21
Configuration: /var/www/html/web/core/phpunit.xml.dist

................................................................. 65 / 81 ( 80%)
................                                                  81 / 81 (100%)

Time: 00:00.289, Memory: 16.00 MB

OK, but there were issues!
Tests: 81, Assertions: 326, PHPUnit Deprecations: 57.
